1. Field of the Invention
The present invention relates to a network configuring method, a network system and a relay apparatus.
2. Description of the Related Art
Today, service provider networks and intra-company networks are required to continue operation for 24-hours in 365 days a year. However, in these networks, configuration change for relay apparatuses often occurs due to change of operation policy of the networks, addition of new subnetworks and the like.
If network service must be stopped until finishing verification of new configuration, complicated configuration change may make service downtime become long. In order to decrease such a state in which users cannot perform network communication as much as possible, a mechanism is necessary for updating network configuration while minimizing system downtime.
For minimizing the system downtime, like a network system shown in FIG.1, redundancy is introduced by providing a current system and a standby system. In the network system, operation in new configuration is checked in the standby system that is formed as a route of routers X, B3, B4, B1 and Y, other than a router B2. Then, after the operation is verified, operation is switched from the current system formed as a route of routers X, A3, A2, A1, and Y, other than a router A4, to the standby system.
By the way, the following patent document 1 discloses a technique for checking consistency of routing data. In the technique, each station forming a network is provided with a routing data area for active operation and a new routing data area. When changing routing data in a station, new routing data is written into the new routing area of the station. At the same time, a command is sent to a routing target station based on the new routing data for checking consistency of the routing data.
[Patent Document 1] Japanese Laid-Open Patent Application No. 7-327050